Maybe Kirby could end up at Beacon Academy. He'd be an odd addition to the student body. His ability to copy powers could make for some really cool interactions during combat classes. For example, he could copy Ruby's speed semblance and use it in a unique way that no one has seen before.
Another plot could involve Kirby being drawn to Remnant because of the powerful auras and semblances. He might start to absorb some of the energy, which causes unexpected changes to his own abilities. This could lead to him having to learn how to control these new powers while also helping the RWBY characters in their fight against the various threats in their world.
One idea could be Kirby arriving in Remnant and being mistaken for a new type of Grimm at first. Then, as the characters get to know Kirby, they realize his unique abilities can be a great asset in battles against Salem's forces.
One plot idea could be human Kirby in a high school setting, dealing with normal teenage problems while also having his Kirby - like powers. For example, trying to hide his ability to inhale large objects from his classmates.
A cool plot might involve a dark force that is affecting both the RWBY world and Kirby's world. This force is causing strange things to happen, like Grimm starting to appear in Dream Land and some of Kirby's enemies showing up in Remnant. Ruby, Weiss, Blake, and Yang meet Kirby, and they initially don't understand him but soon realize his power. They work together to find the source of this dark force. Kirby uses his inhale ability to help them gather information by sucking up some of the smaller Grimm and enemies to learn more about what's going on.
Perhaps a plot where they meet in a dream world and have to find their way back to reality. In this world, they discover new powers within themselves while also forging a stronger friendship. They could encounter strange creatures and solve puzzles to make their way back.
One idea could be that Kirby accidentally gets sucked into the Pokémon world through a strange portal. He then teams up with Pikachu to find a way back home while also helping Pokémon in need. For example, Kirby could use his inhaling ability to save some Pokémon from a forest fire by sucking up the flames.
One idea could be Kirby exploring a new planet where Star Dream has malfunctioned and is causing chaos. Kirby has to find a way to fix it without getting caught by its security systems.
A more complex plot might be that there's a strange rift between the Kirby and Pokemon universes that's causing chaos in both worlds. Kirby and a team of powerful Pokemon, such as Mewtwo and Lugia, must work together to close the rift. Along the way, they learn about each other's powers and abilities, and Kirby has to adapt to the Pokemon battle system while the Pokemon are amazed by Kirby's ability to copy their moves.
One interesting concept could be the combination of Kirby's unique powers, like inhaling enemies and stealing their abilities, with the combat styles and semblances in RWBY. For example, Kirby might gain Ruby's speed semblance and use it in a creative way during battles in the RWBY world.
In RWBY x Kirby fanfiction, the idea of Kirby interacting with the Huntsmen and Huntresses is quite fascinating. Kirby could be seen as a sort of new - age creature in the RWBY universe. His non - human nature and unique abilities would surely catch the attention of the RWBY characters. This could lead to various storylines, like Kirby joining a team of Huntsmen and helping them fight the Grimm in his own unique way, which might involve using his powers to transform into Grimm - like forms he has absorbed.
A Kirby and Sonic the Hedgehog crossover fanfiction would also be cool. Imagine Kirby in the fast - paced world of Sonic. Kirby could learn to run super fast by swallowing a power - up in Sonic's world. They would have to race against time to stop Dr. Eggman from using Kirby's power - stealing abilities to take over both their worlds.
One idea could be that in their human forms, Kirby and Meta Knight are part of a secret society protecting a magical artifact. Kirby, with his innocent yet powerful nature, might be the key to unlocking the artifact's true power, while Meta Knight uses his sword - fighting skills to fend off those who would steal it.